Headache symptoms for a given patient may vary widely from one day to the next, ranging from days when the migraine sufferer is asymptomatic to days when he or she is functionally disabled with severe headache. Increased knowledge of the factors that precipitate migraine ("migraine triggers") will lead to an enhanced ability to accurately predict migraine attacks. This knowledge will be very beneficial for planning pharmacological and behavioral management strategies, many of which are optimally applied either before an attack begins or early in a new attack. Our current understanding of migraine precipitants is almost entirely based on single precipitants studied using cross-sectional, population-based examinations. The effect that multiple precipitants may have on initiating migraine, or the role of hormones in moderating the influence of any single precipitant is unclear. The proposed research is an observational study that utilizes the natural variability of ovarian hormones to examine the relationship between physiological arousal (e.g., heart rate, breath rate, perceived stress), ovarian hormones, and migraine activity in a group of women who are sensitive to hormonal influences (i.e., they have menstrually related migraine). The specific hypothesis behind the proposed research is that migraine activity can be independently predicted by psychophysiological arousal and that this relationship is moderated by hormonal influences. The data from the study will be used to inform a theoretical model that will greatly enhance our understanding of the interplay of this dynamic process. The specific aims are: Aim 1: To examine the relationships between several measures of psychophysiological arousal and headache activity. Aim 2: To examine the relationship between ovarian hormone levels and headache activity. Aim 3: To examine the mediating role of physiological arousal on the relationship between stress and migraine in the context of a potential moderating role of ovarian hormones on these relationships. PUBLIC HEALTH RELEVANCE: According to a recent study, 90% of migraineurs reported functional impairment with their headaches and 53% exhibited severe impairment requiring bed rest. In the United States, migraine results in 112 million bedridden days each year with the cost of migraine to the total American workforce estimated at $13 billion a year in missed workdays and lost productivity. The goal of the present research is to make migraine attacks more predictable by increasing knowledge of headache precipitants thus decreasing the burden of migraine by allowing for earlier intervention during a migraine attack.